1. Field of the Invention
The present invention relates to a fuel cell system including a voltage regulator and an energy storage device which are connected in series to each other, a fuel cell connected in parallel to the serially connected voltage regulator and energy storage device, and a load driven by a combined power source of the energy storage device and the fuel cell. Further, the present invention relates to a vehicle equipped with such a fuel cell system. Such a fuel cell system and such a vehicle equipped with the fuel cell system make it possible to suppress degradation of the fuel cell, and improve the system efficiency.
2. Description of the Related Art
A fuel cell employs a membrane electrode assembly (MEA) which includes an anode, a cathode, and a solid polymer electrolyte membrane interposed between the anode and the cathode. The solid polymer electrolyte membrane is formed by impregnating a thin membrane of perfluorosulfonic acid with water, for example. Each of the cathode and the anode has a gas diffusion layer such as a carbon paper, and an electrode catalyst layer of catalyst particles of platinum alloy or the like (hereinafter also referred to as the Pt catalyst) supported on porous carbon particles. The carbon particles are deposited uniformly on the surface of the gas diffusion layer. The electrode catalyst layer of the anode and the electrode catalyst layer of the cathode are fixed to both surfaces of the solid polymer electrolyte membrane, respectively.
A technique of suppressing degradation of the fuel cell is proposed in JP 2007-005038 A. In the technique proposed in JP 2007-005038 A, power generation of the fuel cell is performed such that an oxidation reduction electric potential where sintering phenomenon of the Pt catalyst (aggregation of the Pt catalyst) occurs is avoided.